I'm sure this is probably already on the cards, but I absolutely love media monkey however am using winamp at the moment because it can play AAC files, please o please put this in the new version and you will have the best player ever!

You can play AAC in MM now, but it will not read the tags. The trick is to copy the plugin from WinAmp (look for in_mp4.dll) and place it in MediaMonkey's plugin folder.

The work around I would use is to make sure all the tag information is in the filename (obviously within reason), then you can "tag" from file name after importing. This information will be stored in the database, but not actually written back to the file.

If that doesn't work (the file is AAC+ or something), try the in_mp3.dll input plugin that is installed together with Winamp5.
Anyway, with in_mp4 and (latest) in_mp3, I'm now able to play all mp4, m4a, aac, aac+ and all special versions of these.